Processing of Porous Hydroxyapatite Scaffold

Abstract

Hydroxyapatite ceramics have been recognized as substitute materials for bone and teeth in orthopaedic and dentistry field due to their chemical and biological similarity to human hard tissue. It is biocompatible and bioactive material that can be used to restore damaged human calcified tissue. Porous hydroxyapatite exhibits strong bonding to the bone, the pores provide a mechanical interlock leading to a firm fixation of the material. Porous hydroxyapatite is more resorbable and more
osteoconductive than its dense counterpart and in porous form the surface area is greatly increased which allows more cells to be carried in comparison with dense hydroxyapatite. The HA prepared from CaNO34H2O and (NH4)2HPO4 by co-precipitation method was phase pure at temperature 12500C. Porous scaffold was prepared by polymeric sponge and incorporation of fugitive such as
naphthalene and PEG. Porous HA prepared from polymeric sponge method had about 70% porosity having pore diameter~400-500μm and pores were interconnected. With increase in PVA contents from 2 to 5 wt% with 40% solid loading the strength of the scaffold increased from 0.69-1.02MPa. It was studied that porosity, pore size and pore inter connectivity depends upon the slurry concentration and the amount of pore former used. In HA-PEG scaffold the porosity increased with PEG 4000 content, while it is decreased for PEG 6000 and pore size depends upon the molecular weight of PEG. In HA-naphthalene scaffold the porosity increased with increased the amount of
pore former. It was observed that range of porosity~1-100μm obtained by varying the amount and size of ceramic and PEG particles. The molecular weight of PEG plays an important role in the morphology, structure, and pore size of scaffold. In-vitro bioactivity and biodegradability studies show that the synthesized scaffold from various methods was bioactive as well as bioresorbable.